Apparatus for the production of combustible gas from solid fuel



Same 1, 393%.. c. WHITFIELD 1,974,373

APPARATUS FOR THE PRODUCTION OF COMBUSTIBLE GAS FROM SOLID FUEL FiledJuly 7, 1950' 2 Sheets-Sheet l Sepia 18, 1934. c. WHITFIELD 1$974,373

APPARATUS FOR THE PRODUCTION OF COMBUSTIBLE GAS FROM SOLID FUEL FiledJuly 7, 19 50 2 Sheets-Sheet 2 Patented Sept. 18, 1934 t. rim-iii,

APPAR Tus FOR THE Hatcheries" 4 or M S KBLF AS FR M. 9!? FU L oiiiirlsfwhiifiidljmoii,"'tifiifiiifuiigiafic Application Juli-7, masterin and'In Great Britain @ugust 3,1929 8 (515615151 (olyizc-ic'j -.i hi' ..1 reat o rel tw q s pr ers where;vv in cgrnbustible material is burnt asfuel for the p du i n of as- 1 i- 1 s g .tW the P e met cd anda p us h v5 lqssi ofleijiciency isprincipally due to the absence of; adequatecontrcl, .f or the air supply and to the cpnditiens under which the air.is brought intov contact with the fuel. The function of the gratex istosupport. the ,fuel,bed so that'the air may 16 have access to theunderside of the ..same., ,The air apertures in the grate are thereforemore or, less suhject to beelosedpneovered,iby the fuel itselfso thatthey arein the aggregate of suflj cient area to admit the air freelyupto the maxidemand forthe grate through the uncov-t cred, portions. TheVolume of air passing-through, the grate as a whole, is thereforedetermined. byQ- the total resistance of. the fuel; bed to.,the;fdrawff, whether ornot such fdrawl is assisted, 26 by'forced or inducedair supply to the grate. ,The

volume of air passing through' any one part of the fuel bed is thereforedep endent upon the total resistanceof such, part of the fuel bed,;-(i.,e. b oth the; resistanceinthebody'of the fuel bed gg'and theresistance at the grate due topartia-l stqppag of theigrate apertures bythe fuel) ,the. local resistance of thegrate itself being substam manynegligible as above explained, and as in 1; practice considerablevariation of fuel bed re- 30 "sistance is bound to exist,unequal;distribution-ofthe air talics place from the very start,resulting nt-u e ua {combu n e -u a b r tion thus-produced tends to,accentuate the origi-, v .-nahdifference: ofresistanceuin the fuelbed-so a. "wartime f ectis ul t ai :U l fl o use tionis at present onlycontrolled by the use of v wea er des f i h av b o Wh h= e-= rherrqp rtQna ee ct Q un q al h i ht .i wh ru ti n t f ll e an a owst io 40' thecombustion to spread from the hi her points of I-eornb tion whichisassisted: by the levelling and se tling action- 0f $1. v ,bed of fueldue to the, weight thereof. 1 Unequal-combustion means un- -equaltemperatures and while a; certain minimum "'temp'erature is required thedifficultyat, present ei iprienced is to maintain such temperature and.atlthe, saiilfe .t ineprev h ri m ii nt ghte awayffrpm the grateresulting from the s a a c m usti wh c Q cu sa an attem t to obtai un fr mb i ri iarau t aoi th a a ugrl a a th gra es. surface, results inblow-pipej action pf theair un -the fuel and the formation of clinkeraway m. "I.::','U'-.-,TI' v: r. i :r-a 3-5512. "Iheformation of clinkerin the fuel mass of vf F -18 I itself rendersit necessari to have depthof v fuel in :the producer than would be rear quired if thezcombustion,could-be, effectedatlthei grate-and equally over-the entire:surface foninl A argas producer itis essential that the .CO-z whichg C0is i produced when andflwhere the clinker-is being formed, must passthrougha mass ofpincandescent carbon inorderto beaconvertedinto 00;:Air; passing through clinkerfiinthebody ofza. as producer, that; is.to,-say,; awayi-fromithe grate results yin practice in an increase ofthe CO2 contentof-thegas. .5 1, s o

{the object ofthe inventiongis toiovercomeworif. mitigate thedisadvantagesas above set out, of the presentmethodsandpl-ant;1 a:

Accordingto the-invention; the-impr edmeth-a 0d cf; obtaining ;unifQ1'-mcombustion of fuel ;;ona. grate for -the production 10f gas. consistsin; pro -i viding a restrictive sectionalqcontrolz of the airupp y was od p e ed n a s faee, ;sueh -control; giving l a ;predeter.mined; re-esistance tq thejpassage-of air; so that each sece-z tion admits only:the; volume ofaair required toe produce its proportion of vcarbonmonoxide tome obtained 1 fromiphe: carbon content :of a the; fuel. 2- 0According tqxfurthen-features; of 'theiinventicnthe-air; apertures oftheyg ratearesuchas to pIOw'; video as; -l,a rge an;are a as possibleconsistent withsupporting-the fuels; Otherfeatures ofthe linven-s y;tion are embodiedinthe description which follows 5 and inthe'appendedclaims.

Upon the accompanying drawings z-e #:I': :1: Fig.=- 1 is a x'plan;-showing the side; andcentralg firebars asused-inconstructing a. grateaccording to one exampleiofthe invention. -;Eig; 2 is .-afront endelevation of some of the firebars ofithegratem i- Fig;,3 is arearendelevation of-,Fig.-2. t ;;Fig.- 4 isa side elevation of the frontvend-of one of the firebarsshowingthe controlrshutter.

-Fig., 5 is a side-elevation .-.of the rearsend of one oftheputside;bars showing the end shutter. 1 Fig- 6 shows cross sectionalviews of the firebars t ai Fig}.

3: $1" imiwu. :13: gig .Fig -H is a cress sectional.,elevationoflonehalf fil h wlowerapart -of a .gas;.-producer showing :amodifiedconstruction of grate according to the enti n--, i

fig t-8; is an en arged elevation showing ithe de s.

sqiv e b rpt hebar ai Ei sILn-J 1:;105

,Fig, 9is a plan of Fig. 8 with parts shown in.

Section. ,t r I g LE s 10; iS

'31: 1 5. vi ,4: fi' i. a cross-sectional'view on line. 10--10 Figfiiis;'gatartiintsiiataami iie and tively close intervals, the notchesextending in" depth to the web. There are therefore longitudinal airslots between each bar as wellas the radiating slots therefrom providedby the notches, the width of the slots being proportioned according torequirements of the grates, in particular as to the fuel to be used. Thebars are provided with an intermediate wider part I on each side betweenthe notches, so as to provide spacing members for the bars intermediateof their length. The grate may be suitably arranged in a generalhorizontal plane although it may be inclined. For completing andcontrolling the supply of air to the iongitudinal chambers providedbetween adjacent grate bars or girders and also to enable clearing the"chambers, shutte'r fiaps are pivoted between the girders, both at thefront and at the back of the grate. Both shutters being mounted forswinging in the same direction, a clearing rake may be used to push outwhatever may have collected, if and when necessary. The front flaps gare between the bars and short so as to leave an opening below them,while the back flaps h are bars. The front flaps g are pivoted on lugsa" cast on the inside of the bars, while the rear flaps h are'pivoted ona rod supported by brackets h 40 secured to the end bars.

As shown in Fig. 6, a is the left hand side fire bar, I) is one of thecentral or intermediate fire bars and c is the right hand side fire bar.Likewise, inthe form of grate construction illustrated in Figs. '7, 8,"9 and 10, there are employed fire barssuitably'shaped and arranged so asto provide a left hand side fire bar, central or intermediate fire barsand a right hand side fire bar. In the form of gas producer grate shownin Figs. '7, 8, 9 and 10 there is a subdivision of the longil'tudinalchamberswhich longitudinal chambers are provided between the'barsandseparate admission of air to each sub-chamber is provided. Thissubdividing of the longitudinal chambers into sub-chambers so as to formthe sub-chamlbers is effected by providing a central bar it in and foreach longitudinal chamber on which bar are secured angle pieces 'marranged in pairs at uniform intervals along the bar and togetherforming dividing members extending across the :longitudinal chamber. Thefirebars are provided with vertical ribs 12 on their sides, spaced atsimilar intervals, with which the dividing members m will normallyregister. The central bar is mounted to be slidable longitudinallyWithi-n' the chamber so that the dividing members m may act as clearersto remove any ash which may have fallen through into the chambers. Theunderside or bottom of the chambers is'forme'd or defined bylongitudinal plates 21., se- Tcured by-screws n to the grate bars andhaving longitudinal slots or notches 0, arranged centrally of thechambers and spaced at the same 1 respectively which are notched at 3.

formed with vertical ribs 12 similar to the ribs b arranged over theends of the bars so as entirely to' 3 close the end of the air chambersbetween the' supply for the subdivision of the longitudinal chamber inwhich it lies. The slots or notches 0, though wider than the grateapertures, are short and of a less area than the grate apertures for thesubdivision, so that while providing eifective control or restricted airsupply according to the invention, they ar large enough to release anyash or bits f fuel which may fall into the chamber.

In the further example as shown in Fig. 11,

there is employed the left hand side fire bar, central or intermediatefire bars, and the right hand side fire bar, respectively designated p,q and r. Said fire bars are formed with flanges 10 q and The notchedflanges take the place of the plates n in the preceding example.Longitudinal bars 15 carrying angle pieces u are provided, similar tothe bars 7:: and angle pieces m, and the firebars are The slots andspaces at the grate surface are such as to provide as large an airsupplyarea as possible consistent with practical requirements as tostrength and durability. Those in the grate illustrated herewith aresuitable in size for most IQ of the usual fuels but the same area may beobtained with a greater number of narrower slots and spaces to provide asurface for use withfine or crushed fuel. V

Experimetally, a suitable inlet area was found 1105; to be about onesixth or less of the total area of i the apertures of the grate sectionassociated therewith, or about one eighteenthof the'ar'ea of the saidgrate section surface. Useful control may, however, be obtained evenwithan inlet area for each chamber which is as much as oneeighth of the areaof the said grate section surface. For efiicient working a grate sectionof not larger than half a square foot is preferred and not less thanfour sections are desirable inthe 1 grate.

In use, the restriction or control of the'air supply is obtained at theentry to the air charnhere instead of at the grate surfaca so 'thata lowvelocity, steady and uniformly limited and" distributed supply of airpasses up through the air spaces of the grate and renders it possible toproduce gas containing a smaller percentage of C02 on a thin bed of fuelthan is possible ona deep bed to which this method ofcontrol has not-=been applied. It therefore follows, also, thatai producer having thisgrate will be more efficient since the resistance to the fiow of gaswill be more uniform, a lower temperature in the gas will reduce theloss of sensible heat and also the wear and tear incidental to highertemperatures, com bustion being effected under conditions of lower airvelocity results in temperatures sufficiently hi h to effect thecomplete gasificaticnof thefixed carbon, yet low enough to prevent thedis sociation of the methane and other fixed hydro-' carbons. Theimproved grate, as a gas producer, is capable of burning small fuel,orrefuse, and of providing a high quality of gas therefrom.

It will be obvious that variations in constructional details may bemade, without departing from the invention, the essential feature ofwhich" is the provision of a grate wherein the air supply is controlledin such manner as to allow of uniform distribution, that is, all partsof the grate its area are under control, individually and (or)collectively, and capable of uniformity of action.

1. A grate for the combustion of figelfonthe production of a combustiblegas comprising bars arranged side by side and having upper and lowerflanges extending laterally from the sides of the bars so as to formseparate closed air spaces between them, means providing verticalpartitions between the fire bars subdividing said spaces into chambersalong the length of the bars notches in the edges of said upper flangesforming air outlet apertures leading from said chambers, and notches insaid lower flanges which collectively provide an air admission aperturefor each chamber, the total area of the apertures in the lower flangesbeing not more than one-third of the total area of the apertures in theupper flanges.

2. A grate for the combustion of fuel for the production of combustiblegas comprising bars arranged side by side and having upper and lowerflanges extending laterally from the sides of the bars so as to formseparate closed air spaces between them, means providing verticalpartitions between the fire bars subdividing said spaces into chambersalong the length of the bars, notches in the edges of said upper flangesproviding outlet apertures leading from said chambers, notches in saidlower flanges which collectively provide an air admission aperture foreach chamber, the total area of the apertures in the lower flanges beingnot more than onethird of the total area of the apertures in the upperflanges, and the ratio of air inlet area to the area of the gratesurface apertures being uniform for the whole of the grate area.

3. A grate for the combustion of fuel for the production of acombustible gas comprising bars arranged side by side and having upperand lower flanges extending laterally from the sides of the bars so asto form separate closed air spaces between them, slidable bars betweenthe fire bars, vertical partitions on said slidable bars for subdividingthe chambers along the length of the bar notches in the edges of saidupper flanges forming air outlet apertures from said chambers, notchesin said lower flanges which collectively provide an air admissionaperture for each chamber, the total area of the apertures in the lowerflanges being not more than one-third of the total area of the aperturesin the upper flanges.

4. A grate for a gas producer comprising longitudinally extending gratebars each having a vertically extending web section and upper and lowerflanges that extend laterally from the web section, the adjacent gratebars being constructed so that there is provided between them andbetween the upper and lower flanges thereof air spaces that provideseparate air supply chambers, the upper flanges of the grate bars beingnotched to form the grate surface apertures through which air passesfrom the air supply chamber to the fuel, and means for subdividing thespace between adjacent bars into several relatively small air supplychambers, means in the lower wall portion of each chamber for theadmission of air to said chambers but only in a restricted manner, theconstruction of said last named means being such that the air inlet areafor any one chamber is not larger than one-third of the grate surfaceapertures leading from said chamber.

5. A grate for a gas producer comprising grate bars constructedaccording to claim 4, being further characterized in that the upperflanges of the bars at the edges of the notched portions are of such awidth that at least some of those portions of the adjacent flanges arespaced apart and that the space between those portions of these adjacentflanges form part of said grate surface apertures.

6. A grate for the combustion of fuels for the production of acombustible gas, said grate comprising bars arranged side by side andhaving upper and lower flanges extending laterally from the sides of thebars so as to form with the associated parts of the grate separateclosed air chambers between the bars, the upper flanges of said barsbeing constructed and arranged so that they collectively form anapertured grate fuel supporting surface through the apertures of whichair from the air chambers can flow to the fuel in the grate, the grateconstruction also being such that in a wall portion of each chamberother than that part provided by an upper flange there is provided aninlet aperture lead-- ing to an air chamber to which the particularaperture corresponds, the inlet aperture for each chamber being not morethan one-third of the grate surface apertures leading from thecorresponding chamber, and vertical partitions between the fire bars,which vertical partitions carry members whereby each chamber in whichthe partition is located is'subdivided.

7. A grate for a gas producer comprising a fuel-supporting member formedinteriorly with a plurality of separate chambers, said member having airoutlet apertures in its upper face extending from each of said chambersand having air inlet apertures in its lower face extending from each ofsaid chambers, the total area of the said air inlet apertures for eachchamber being not more than one-third of the total area of the saidoutlet apertures for the same chamber.

8. A grate for the combustion of fuel for the product of a combustiblegas comprising bars arranged side by side and having upper and lowerflanges extending laterally from the sides of the bars so as to formseparate closed air spaces between them, slidable bars between the firebars, vertical partitions on said slidable bars for subdividing the airspaces along the length of the bars into chambers, notches in the edgesof the upper flanges forming air outlet apertures from said chambers,notches in said lower flanges which collectively provide an airadmission aperture for each closed air space, the total'area of theapertures in the lower flanges being not more than one-third of thetotal area of the apertures in the upper flanges, and said grate beingdivided 7 in not less than four sections and none of the sections intowhich the grate is divided being larger than a half square foot.

CHARLES WHITFIELD.

